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Mechanical Permit in Issaquah, Washington

Mechanical and fuel gas work in Issaquah is reviewed under the 2021 International Mechanical Code together with the fuel gas codes named in the Construction Administrative Code.

Verified 2026-09-16 · Source

When you need this permit

  • “2021 International Mechanical Code – Chapter 51-52 WAC” (CAC 101.2)
  • “2021 National Fuel Gas Code (NFPA 54) – Chapter 51-52 WAC” and “2021 International Fuel Gas Code – Chapter 51-52 WAC”
  • “2020 Liquefied Petroleum Gas Code (NFPA 58) – Chapter 51-52 WAC” — the one document named at a 2020 edition
  • Each has its own adopting section: IMC 16.04.040, 16.04.050, 16.04.060 and 16.04.070

Required documents

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Fee schedule

Mechanical permit
CAC 109.2 charges mechanical permits through the city's published schedule: “For buildings, structures, gas, mechanical and plumbing systems, or alterations requiring a permit, a fee for each permit… Show full citationCAC 109.2 charges mechanical permits through the city's published schedule: “For buildings, structures, gas, mechanical and plumbing systems, or alterations requiring a permit, a fee for each permit shall be paid as required, in accordance with the schedule as established by the City of Issaquah.” Additional inspection and plan review charges come from Table D, which was not read for this entry.
Per CAC Table A/D on valuation
Refund if withdrawnCAC 109.7: “not more than 80 percent of the permit fee paid when no work has been done”, and the same cap on plan review fees where an application is withdrawn or cancelled before any plan review is done.
Up to 80% refunded if no work is done
Refund if charged in errorCAC 109.7: “The Building Official may authorize full refund only if the fee was charged in error or the wrong type of permit was selected…”
100% only if charged in error

Review timeline

Plan review
Not published — contact the department

How long did your Mechanical Permit permit actually take in Issaquah?

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Inspection process

    Tips

    • Check the NFPA vintage separately from the IMC. Issaquah names the Liquefied Petroleum Gas Code (NFPA 58) at its 2020 edition while the IMC, the International Fuel Gas Code and NFPA 54 are all 2021 — and Lake Stevens publishes exactly the same split, which is why it reads as the state-adopted vintage rather than a slip.
    • Fuel gas is not folded into one section here: the chapter gives NFPA 54, NFPA 58 and the International Fuel Gas Code their own adopting sections at IMC 16.04.050, 16.04.060 and 16.04.070, all routed through Chapter 51-52 WAC.

    Frequently asked questions

    Issaquah requires a mechanical permit for: “2021 International Mechanical Code – Chapter 51-52 WAC” (CAC 101.2); “2021 National Fuel Gas Code (NFPA 54) – Chapter 51-52 WAC” and “2021 International Fuel Gas Code – Chapter 51-52 WAC”; “2020 Liquefied Petroleum Gas Code (NFPA 58) – Chapter 51-52 WAC” — the one document named at a 2020 edition; Each has its own adopting section: IMC 16.04.040, 16.04.050, 16.04.060 and 16.04.070. If your project isn't listed, confirm with City of Issaquah – Development Services at (425) 837-3000 before starting work.

    In Issaquah, the published Mechanical permit is: Per CAC Table A/D on valuation. Additional published fees: Refund if withdrawn — Up to 80% refunded if no work is done; Refund if charged in error — 100% only if charged in error. These are the jurisdiction's own published figures — see the fee schedule table and source citations on this page.

    Issaquah does not publish a plan-review timeline for this permit. Contact City of Issaquah – Development Services at (425) 837-3000 for current turnaround.

    You'll need: Mechanical Permit Application. See the required-documents checklist on this page for details on each.

    Apply through City of Issaquah – Development Services at 130 E Sunset Way, Issaquah, WA 98027. Phone: (425) 837-3000. Official information: https://www.issaquahwa.gov/.

    Issaquah, Washington has adopted: ISSAQUAH WROTE ITS OWN ADMINISTRATIVE CODE RATHER THAN ADOPTING THE MODEL ONE. IMC 16.04.010 sets out a full “Construction Administrative Code” (CAC): “101.1 Title. These regulations shall be known as the Construction Administrative Code (CAC) of the City of Issaquah, hereinafter referred to as ‘this code.’” Chapter 16.04 runs to roughly 257,000 characters, most of it local administrative text rather than adoption-by-reference.; THE NAMED LIST — CAC 101.2 Applicable Codes: “2021 International Building Code – Chapter 51-50 Washington Administrative Code (‘WAC’); 2021 International Residential Code – Chapter 51-51 WAC; 2021 International Mechanical Code – Chapter 51-52 WAC; 2021 National Fuel Gas Code (NFPA 54) – Chapter 51-52 WAC; 2020 Liquefied Petroleum Gas Code (NFPA 58) – Chapter 51-52 WAC; 2021 International Fuel Gas Code – Chapter 51-52 WAC; 2021 Uniform Plumbing Code – Chapter 51-56 WAC; 2021 Washington State Energy Code – Chapters 51-11C and 51-11R WAC; … 2021 International Existing Building Code – Chapter 51-50 WAC; 2021 International Property Maintenance Code; 2021 International Wildland Interface Code; 2021 International Swimming Pool and Spa Code – Chapter 51-51 WAC”.; NFPA 58 IS 2020 WHILE EVERYTHING ELSE IS 2021 — AND LAKE STEVENS PUBLISHES THE SAME SPLIT. Two independently drafted codes in this set both name the Liquefied Petroleum Gas Code at its 2020 edition alongside 2021 for the IMC, IFGC and NFPA 54. The agreement of two unrelated cities is why this is recorded as the state-adopted vintage rather than flagged as a typo.; BUT THE SAME CHAPTER DELEGATES IN ITS DEFINITIONS, WHICH IS WHERE A BINDING CAN HIDE. CAC 101.2.1 defines each acronym used throughout the code as the LATEST edition: “‘IBC’ means the latest edition of the International Building Code promulgated by the International Code Council as adopted by the City”, and likewise for the IEBC, IMC, IPMC, IRC, UPC, “energy code” and “housing code”. Those definitions resolve circularly back to what the City has adopted — the named 2021 editions in 101.2 — so 2021 is what applies; but a reader who consults only the definitions would find no year at all.; THE ELECTRICAL DEFINITION IS THE ONE THAT DROPS THE QUALIFIER. Every other acronym is defined as the latest edition “as adopted by the City”. CAC 101.2.1(11) reads: “‘NEC’ means the latest edition of the National Electrical Code promulgated by the National Fire Protection Association.” — with no “as adopted by the City”. Consistent with that, the section list of Chapter 16.04 contains NO electrical adoption section at all: it runs CAC, IBC, IRC, IEBC, IMC, NFPA 54, NFPA 58, IFGC, UPC, energy code, IPMC, ISPSC, IWUIC 403.2.4, documents to be filed, and violation/penalty.; IRC APPENDICES: “IRC Appendix F – Radon Control Methods, Appendix Q – Tiny Houses, and Appendix U – Dwelling Unit Fire Sprinkler Systems are included in adoption of the International Residential Code.” Lake Stevens takes F and Q; Issaquah adds U. Otherwise “Provisions in the appendices shall not apply unless specifically adopted” (CAC 101.2.2).; A STATE-LEVEL CONSTRAINT ON LOCAL APPENDIX ADOPTION IS QUOTED IN THE CODE: “An appendix adopted by the City that affects single-family or multifamily residential buildings as defined in RCW 19.27.015 shall not be effective unless approved by the State Building Code Council pursuant to RCW 19.27.060(1)(a).” (CAC 101.4.2.1).; The Wildland-Urban Interface code is adopted only in part — IMC 16.04.111 is titled “International Wildland-Urban Interface Code Section 403.2.4 adopted.”, a single section, while CAC 101.2 lists the whole “2021 International Wildland Interface Code”. NOTE ALSO THE NAME VARIANT between those two places: “Wildland Interface” in the applicability list, “Wildland-Urban Interface” in the section heading.; The fire code is NOT in this chapter: the chapter's own footnote reads “For adoption of the International Fire Code, see Chapter 16.06 IMC.”, and Chapter 16.06 was not opened for this entry.; NOT OPENED FOR THIS ENTRY: IMC 16.06 (Fire Code), 16.08 (Fire Zone), 16.10 (Conversion Condominium), 16.20 (Site Renovation), 16.24 (Improvements in Hazardous Areas), 16.26 (Clearing, Grading, and Stormwater Management), 16.36 (Areas of Special Flood Hazard), 16.38 (Fats, Oils and Grease Regulations), 16.40 (Sustainable Building Regulations), and the whole of the separately published Land Use Code (IMC Title 18 / LUC Parts I–VIII).. Local amendments apply — see the Issaquah overview page for the full list.

    CAC 101.2 lists the “2021 International Mechanical Code – Chapter 51-52 WAC”, the “2021 National Fuel Gas Code (NFPA 54) – Chapter 51-52 WAC”, the “2020 Liquefied Petroleum Gas Code (NFPA 58) – Chapter 51-52 WAC” and the “2021 International Fuel Gas Code – Chapter 51-52 WAC”. NFPA 58 is the only one named at 2020; the same 2020/2021 split appears independently in Lake Stevens' code.

    Sources & verification

    Verified against official sources. Last reviewed 2026-09-16.

    Fees, timelines, and adopted codes are researched from each jurisdiction's published records — see how we verify. Requirements change and vary by project, so always confirm the current details with the Issaquah building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.

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